In commerce and industry today, the useful life of corrodible items may be extended and/or preserved by providing corrosion inhibitors which protect the corrodible item from the adverse effects of its ambient environment. Elements or compounds which are normally of primary concern are gases such as oxygen, water vapor, sulfides, carbon dioxide, aqueous aerosols containing salts or acids, and the like. Among the common indications of corrosion manifested in useful metallic articles are oxidation, pitting, tarnishing, mottling, or discoloration of the surfaces of these items. Metals which are frequently found to be susceptible to corrosion under normal atmospheric and ambient conditions are iron, copper, brass, aluminum, silver, and alloys of these metals. Corrosion inhibitors, particularly vapor phase corrosion inhibitors, have been found useful in protecting certain corrodible items against reaction with elements or compounds which may be found within their environment, and thereby losing their effectiveness, reducing their useful life, or otherwise diminishing their value. Such protection is typically needed during times of packaging, handling, shipment, or during end use.
In the past, it has been known to provide a package or other enclosure which includes one or more inhibiting compounds along with the corrodible item or items to be protected. Additionally, articles have been protected from corrosion by means of protective coatings in the form of solids, liquids, greases, or pastes. However such coatings tend to provide only temporary benefit, and may present certain disadvantages to normal handling and packaging. Furthermore, removal of such protective coatings may be needed prior to article use, and such removal may present problems either due to incomplete removal, or the costs of such removal.
Solid phase and liquid phase compounds have been used in the past as vapor phase corrosion inhibitors. These materials typically have sufficient volatility to either evaporate or sublime to provide a substantially constant availability of the vapor phase inhibitors. In other words, volatile corrosion inhibitors typically emit vapors which protect corrodible surfaces through the deposition or condensation of a protective film or coating upon the surface. In order to be assured that a constant supply of inhibitor be present, adequate quantities of the solid phase or liquid phase corrosion inhibiting compounds must be provided, with the corrosion inhibiting compounds being released at or adjacent to the treatment location. Examples of vapor phase corrosion inhibitors and delivery vehicles for such inhibitors may be found in U.S. Pat. Nos. 4,973,448, 5,139,700, 5,209,869, 5,715,945, 6,028,160, 6,617,415, and U.S. Pat. No. 7,118,615, herein incorporated by reference. While some current vapor phase corrosion inhibitors are non-toxic and environmentally benign, many originate from non-renewable petrochemical feed stocks, which are viewed negatively by some consumer segments. Therefore, there is need for bio-based vapor phase corrosion inhibitors sourced from renewable resources, particularly if such materials are of equivalent or lower cost than currently available products. While several bio-based/renewable materials have shown corrosion inhibitor properties when used in de-icer compositions (see for example U.S. Pat. Nos. 4,668,416, 6,149,834, 6,416,684, and 2009/0302276), we have not found any reference or suggestion indicating that biological or agricultural materials could be used as vapor phase corrosion inhibitors. Thus, it has been surprisingly found that molasses products can be used as vapor phase corrosion inhibitors.